By Alok Jha
Wednesday 23 July 2008

A Concentrating solar power (CSP) plant in Spain that uses
panels to reflect light onto a central tower to produce
electricity. Similar plants are proposed for north Africa.
Photograph: AP

A tiny rectangle superimposed on the vast expanse of
the Sahara captures the seductive appeal of the audacious plan to cut
Europe's carbon emissions by harnessing the fierce power of the desert
sun.

Dwarfed by any of the north African nations, it
represents an area slightly smaller than Wales but scientists claimed
yesterday it could one day generate enough solar energy to supply all of
Europe with clean electricity.

Speaking at the Euroscience Open Forum in Barcelona,
Arnulf Jaeger-Waldau of the European commission's Institute for Energy,
said it would require the capture of just 0.3% of the light falling on
the Sahara and Middle East deserts to meet all of Europe's energy
needs.

The scientists are calling for the creation of a
series of huge solar farms - producing electricity either through
photovoltaic cells, or by concentrating the sun's heat to boil water and
drive turbines - as part of a plan to share Europe's renewable energy
resources across the continent.

A new supergrid, transmitting electricity along high
voltage direct current cables would allow countries such as the UK and
Denmark ultimately to export wind energy at times of surplus supply, as
well as import from other green sources such as geothermal power in
Iceland.

Energy losses on DC lines are far lower than on the
traditional AC ones, which make transmission of energy over long
distances uneconomic.

The grid proposal, which has won political support
from both Nicholas Sarkozy and Gordon Brown, answers the perennial
criticism that renewable power will never be economic because the
weather is not sufficiently predictable. Its supporters argue that even
if the wind is not blowing hard enough in the North Sea, it will be
blowing somewhere else in Europe, or the sun will be shining on a solar
farm somewhere.

Scientists argue that harnessing the Sahara would be
particularly effective because the sunlight in this area is more
intense: solar photovoltaic (PV) panels in northern Africa could
generate up to three times the electricity compared with similar panels
in northern Europe.

Much of the cost would come in developing the public
grid networks of connecting countries in the southern Mediterranean,
which do not currently have the spare capacity to carry the electricity
that the north African solar farms could generate. Even if high voltage
cables between North Africa and Italy would be built or the existing
cable between Morocco and Spain would be used, the infrastructure of the
transfer countries such as Italy and Spain or Greece or Turkey also
needs a major re-structuring, according to Jaeger-Waldau.

Southern Mediterranean countries including Portugal
and Spain have already invested heavily in solar energy and Algeria has
begun work on a vast combined solar and natural gas plant which will
begin producing energy in 2010. Algeria aims to export 6,000 megawatts
of solar-generated power to Europe by 2020.

Scientists working on the project admit that it would
take many years and huge investment to generate enough solar energy from
north Africa to power Europe but envisage that by 2050 it could produce
100 GW, more than the combined electricity output from all sources in
the UK, with an investment of around €450bn.

Jaeger-Waldau also believes that scaling up solar PV
by having large solar farms could help bring its cost down for
consumers. "The biggest PV system at the moment is installed in Leipzig
and the price of the installation is €3.25 per watt," he said. "If
we could realise that in the Mediterranean, for example in southern
Italy, this would correspond to electricity prices in the range of 15
cents per kWh, something below what the average consumer is paying."

The vision for the renewable energy grid comes as the
commission's joint research centre (JRC) published its strategic energy
technology plan, highlighting solar PV as one of eight technologies that
need to be championed for the short- to medium-term future.

"It recognises something extraordinary - if we don't
put together resources and findings across Europe and we let go the
several sectors of energy, we will never reach these targets," said
Giovanni de Santi, director of the JRC, also speaking in Barcelona.

The JRC plan includes fuel cells and hydrogen, clean
coal, second generation biofuels, nuclear fusion, wind, nuclear fission
and smart grids. De Santi said it was designed to help Europe to meet
its commitments to reduce overall energy consumption by 20% by 2020,
while reducing CO² emissions by 20% in the same time and increasing
to 20% the proportion of energy generated from renewable sources.

Backstory

High voltage direct current (HVDC)
transmission lines are seen as the most efficient way to move
electricity over long distances without incurring the losses experienced
in alternating current (AC) power lines. HVDC cables can carry more
power for the same thickness of cable compared with AC lines but are
only suited to long distance transmission as they
require expensive devices to convert the electricity, usually generated
as AC, into DC. Modern HVDC cables can keep energy
losses down to around 3% per 1,000km. HVDC can also be used to
transfer electricity between different countries that might use AC at
differing frequencies. HVDC cables can also be used to synchronise AC
produced by renewable energy sources.

· This article was amended on Thursday July 24
2008. The scientist referred to above from the European commission's
Institute for Energy is Arnulf Jaeger-Waldau, not Jaeger-Walden. This
has been corrected.